What should I say in a 3 page diary of a made-up person from the Renaissance?i have to write a creative writting peice of a diary from a character...

What your teacher is likely to want to see here is
evidence that you have understood what you have read or been told about the changes of
the Renaissance.  So, the best thing for you to do would be to look at all the things
that your teacher or book has said about what things were like in the Renaissance.  Then
try to imagine how such things would impact a specific person who was living during that
time.

For example, a major change going on during the
Renaissance was a move toward humanism and away from simply relying on the authority of
the Church.  One way this was shown was through changes in art.  So maybe you could have
an entry in which you talk about having gone to see some famous piece of art that was
created during this time.  You could talk about your reactions to it.  Maybe you could
say that it was really realistic and centered on humans rather than God.  Then you could
talk about wondering if that is the right way for art to
be.

So, just look for major trends in the Renaissance and
try to imagine how a specific person would have experienced
them.